/Engine/Plugins/Interchange/Runtime/Source/Parsers/GLTFCore/Public/GLTFMaterial.h
enum EPackingFlags { None = 0x0, NormalRG = 0x1, OcclusionRoughnessMetallic = 0x2, RoughnessMetallicOcclusion = 0x4, NormalRoughnessMetallic = NormalRG | 0x8, }